One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,5,8)(3,7,4,6)(9,10)(11,19)(12,23)(13,17)(14,18)(15,21)(16,27)(20,34)(22,33)(24,38)(25,30)(26,37)(28,39)(29,35)(31,40)(32,36)(1,3,5,4)(2,6,8,7)(9,11)(10,15)(12,24)(13,21)(14,22)(16,28)(17,19)(18,29)(20,26)(23,34)(25,35)(27,36)(30,33)(31,32)(37,38)(39,40)(1,3,5,4)(2,7,8,6)(9,12,25,40)(10,16,30,37)(11,20,35,39)(13,26,14,27)(15,28,33,34)(17,31,18,23)(19,32,29,38)(21,24,22,36)(1,4,5,3)(2,7,8,6)(10,17)(11,21)(16,31)(18,30)(20,24)(22,35)(23,37)(36,39)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.